Alternating-current motor.



PATENTED SEPT. 1, 1908 M. MILCH. ALTERNATING CURRENT-MOTOR. APPLICATION FILED 0011.12, 1903. RENEWED OUT. 5, 1907.

Inventor. MAURICE MILCH.

BY I

wi bnegses.

ATTY.

PATENTED SEPT. 1, 1908 M. MILGH.

ALTERNATING CURRENT MOTOR.

APPLICATION Plum 00pm, 190s. RENEWED 001'. 5, 1901.

3 QHEETS-BHEET 2.

wltrfiesse s: inventor:

Maurice Milch. walk/{17M fltty No. 897,475. PATENTED SEPT. 1, 190a M. MILGH.

ALTERNATING CURRENT MOTOR. APPLICATION runnocrm, 190a. nnnnwgn 0M. 5, 1901.

8 SHEETS-SHEET (Iv Witnesses InVentr; I ,4 Maurice M il'ch.

(4 Mihb r Att'y.

UNITED STATES r ENT OFFICE;

MAURICE MILCH, OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF NEW YORK.

ALTERNATING-O'O'RBENT MOTOR.

Specification of Letters Patent.

Patented Sept. 1, 1903.

Application mm 0mm 12, 1903, Serial No. 17am. Renewed Ootober i, 1901. Serial No. 896,024.

To all whom it may concern:

Be it known that I, MAURICE MILCH, asub- 'ect of the King of Hungary, residing at henectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Alternating-Current Motors, of which the followin is a specification.

y invention relates to alternating-current motors, and has for its main object to provide a simple'and efiicient type of single-phase motor, which ma be conveniently controlled both as to spee and direction of rotation Viewed in one aspect, my invention consists of an alternating-current motor having a prima'ry winding distributed over a portion only of the primary member, a secondary member provided with a commutator and with short-circuiting brushes and having its circuits arranged to render effective only those ortions of the secondar winding that are a. jacent to the main field winding, and means for producing an auxiliary field at an angle to the field produced by the primary winding; I I

In another as ect my invention consists in arranging an a ternating-current motor ofthe commutator type with a distributed primary winding and an auxiliary winding'on the primary member concentrated in large slots and connected in series with the brushes; this arrangement of windings'improving the efficiency of commutation.

. My invention also includes a novel arrangement of shortcircuited conductors for preventing magnetic leaka e.

My invention' will be/ better understood by reference to the following description taken in connection with the accompanying drawin s, in which I I igure 1 is a simple diagram illustratin one embodiment 'of my invention in which the auxiliaryfield is produced by means of a separate windin on the primary member;

Figs. 2, 3, 4 an 5. are diagrams'illustrating modifications in which the primary winding extends over a portion only of the primary -.member and in which the brushes on the commutator of the secondary member maintam in local closed circuits on] those portrons of the secondary winding it at are ad'a cent to the primary WlndlIilfi; igs. 6 an 7 arediagrams illustrating st further modifications in which the auxiliary magnetic field 15 produced by means of'currents which are and which may be termed the mam inducing windin B which is shown as an ordinary cated on the prnnarlymember on the portion of ary winding. T e other .Figs. 8, 9, 10 and 11 are diagrams showin details of construction-of the'n'otor to whi my invention relates. I

Referring first to Fig. 1, a: 2: represent single-phase supply mains to which is connected the primary winding A of a singlephase motor. The winding which extends, over a portion only of the primarp member,

winding, is arranged to generate a primary field a ong the line 1-1. member of the motor is provided with a closed ramme ring winding.- This windi is provided with a commutator on whic bear the brushes 3 4, located alo the line of the primary magnetization. T e primary winding operates to enerate currents by induction in the winding on the secondary member and in the articular arrangement shown in this fi ure tl iese currents are caused to flow through an auxiliary winding C 10- the primary mem er not occupied by the main inducing winding,-and arran ed to produce a magnetization alo This magnetization is at ri t angles to the magnetic axis of the secon' ary winding and is in a position to produce a torqueilpon the rotary member of the motor;

The motor may be controlled by controlling the current in any of its windings in any of the well known wa s. As those portions of the secondary win ing which are not covered by correspondi portions of, the primary winding are lia l fie to set up large selfinduced fields, it will be found necessary in actual constructioneither to rovide the primary member of the motor with a distrib- .uted winding extending around the entire circumference, or so to arrange the circuits of the secondary windin asto render effective only those' arts of t e seconds that are ad acent to the main fiel winding; This may be accomplished by arrangin the commutator brushes to maintain 1n ocal closed circuits onl those partsof the second- I ortions of the 105 secondary windi which' ecause of their position in the prrmary'field are relatively mefiicient in generating electromotive force,

are kept on open circuit. This arrangement results in producing on the secondary mom 11o The secondary 'the ine 2-2. I

winding 1011 current needs to be handled at each brush.

her the same distribution of current, and consequentl the same distribution of ma netomotive orce as that of the main in ucing winding on the primary, so that leakage fields are avoided: This'arran ementrecessitates' the use of four brushes or a two-pole motor, but with these four brushes placed adjacent to the ends of the rimary windin whatever flux passes throng the'air-gap W1 necessarily interlink both the primary and the effective portions ofthe secondary windings and the efficiency of the motor-will be increased. Moreover, the added complication, due to the increased number of brushes, is offset' by the fact that only one-half of the In the arrangement shown in Fig. 2, the

. auxiliary winding is'divided in two sections and one of the sections is connected in circuit with each of the two sets of brushes 5 6 and 7 8. With such an arran ement, it is necessary for satisfactory WOl'iiIWf that the electromotive forces between the two sets of brushes and the resistances of the .two sections of the auxiliary winding shall be exactly the same, and in order to avoid a possible un balancing, due to either of the above causes, I have devised the arrangement shown in Fig. 3, in which the two sections of the auxiliary winding are superposed upon the pri 'mary member.

The arrangement of brushesshown in Figs. 2 and 3 necessitates the separation of the secondary circuit into two independent circuits, in order to prevent thefiowof currents in the idle turns of the secondary winding. This arrangement is, therefore, open to the objection that, besides reguiring four brushes 'per.pole instead of two,

our instead of two circuit connections have to be controlled for v reversing the direction of rotation of the motor. Fig. 4 shows an arrangement for overcoming this difficulty, although it is less efiicient. directly short-circuited and the current for Here the brushes of one set are the auxiliary winding is supplied from the other set of brushes.

Fi n 5 shows still another arran emeiit in i which all unbalancing is prevente In the arrangement shown in this figure,' brushes 5 and 7 are connected to the terminals of one of the windings D. of a differential choke coil, thiizother brushesfi and. Sbei-ng connected to the terminals of another similar winding D These windings offer no resistance to the flow ofcurrent from the secondary winding'to the auxiliarywinding, the terminals of which are connccted. at the middle points of the two windings of the choke coil, and they preserve a balance of potential between the brushes 5- 7 and 6-8, while permitting only a small magnetizing current to flow therethrough.

In the arrangement shown in Figs. 6'' and 7, the auxiliary field instead of being generated "by alseparate winding" on the primary memfof turns in the transformer windings.

reversed by reversing the conneetiens o her is produced by means of currents which are caused to flow through the idle portions- 3 the secondary winding, In the arrangement shown in Fig. 6, the brushes 5 and 6 are short-circuitcd through a transformer winding E, and the brushes 7 and 8 are short-circuited through a similar winding E. These -windings assist each other in producing a magnetlc. flux in the core on wlnch they are wound, and this flux induces an electrometive force in a secondary winding F, the terminals of which are connected to the middle points of the transformer wimlings E and a, so that'a current, due to the electromotive forcrgenerated in the secondary coil F, is led back differentially through the twotransformer windings E and E to those portions of the secondary winding between the brushes 5-7 and 6--8. The current flowing in these portions of the secondary winding serves to produce the auxiliary field alongthe line 22, and this field acting in conjunction with the currents in-the active portions of the secondary winding, produces rotation of the motor the same as in the ar rangements shown in the earlier figures of the drawing. The direction of rotation may be. controlled by reversing the terminal connections of the windings E and E or of the winding F, and the s eed of the mot-or may be controlled either rom the primarycireuit in any desired manner or from thesecondary by the addition of any suitable regulating means as, for example, by the inclusion in the sec,- ondary' exciting circuit of a regulating resistance, or by varying the relative nulrnber 1g. 7 shows another arrangement '"in which the auxiliary'field is produced by means of ourrents 'ffiowing through. idle portions of the secondary winding, but in this case these currents, instead of being obtained from the secondary member, aretaken from the second- I ary of a transformer, the prima of 'whichis included in circuit with the primary windings of the motor. The twosets ofzhrushes 56 and 7-8 are directly short-circuited by means of conductors 9 and 10,"and these conductors serve both to complete the local closed circuits for the active. portions of the secondary winding, and also to conduct the'eXci-ting current ffronithe secondary windin G of the transformer to the. idle. portions 0 ,thefse'c-l bndary' Winding of the motor. Inf this arrangement the direction of'rotation'mag lfie t e secondary winding G or of the gri ry wind; ing H of the transformer an the speedof the motor may be eont'rolledeither from the primary circult orfrom the secondary circuit y any of themethods already described.

In the actual construction of a motor in' I accordance. with the principles of my present invention, I prefer to arrange v-the prnpary; 139

and auxiliary windings on the primary memductors ofwliich conductors shown in Fi s. 10 and 11.

v trated in large slots, in ordento reduce the reactance of the said winding, and so positioned on the core that the may at the-same time serve the additional unctions of reducing the reactance of commutation and of offering a weak field for the cutting of the coils short-circuited by the brushes. The construction shown n'rFig. 9 is similar to that shownin Fig. 8, with the exception that the prima winding is shown distributed only over t at portion of the primary member which is adjacent to the corresponding shortcircuited portions of the secondary winding and the auxilia winding ismade up of coils concentrated in arge slots at the ends of the primary winding: .In this form of myiinvention it maybe found to be of advantage to further decrease the reactance of the aux iliaryfield winding, and to this end I have devised the arrangement of short-circuitixg s shown in Fig. 10, the lea age flux tending to increase the reactance of the auxiliary windm'gflows, as indicated by the'dotted lines and arrows, in relatively opposite directions throughthe twohalves of the unwound portions of the primary core. I therefore provide thisportion of the primary core with a two-partshort-circuited coil, the middle conass through a hole or slot in the middle of-tiie unwound portion. The turns of thetwohalves of the short-circuited coil relatively-Ereversed, so'that any leakage nux aroun the coils of the auxilia winding tends to induce currents in bet parts of the short-circuited coil K in the same relative directions, as indicated by the arrows in Fig. 11'.

' Thus, the short-.ci'rcuited coil acts as a screen tending to prevent magnetic" leakage. I'It will be noted that the short-circuitedfcoil has no screening effect on the. magnetic flux due to the primary winding,,for thisfiux passes through both halves of the'shorbcircuited coil in the same direction, thereby inducing electromo'tive forces in-the two halves that are opposed to each other.

In the arrangements above described, as

in the repulsion motor, the ratio of voltages in the rlm'ary and secondary members may be me e anything desired by properly choosing therelative number of turns in the primary andsecondary windings, while the ad vantages of the-series motor as regards ease of speed control ahdcontrol of direction ofrotatlon, are obtained.

In the drawings the motor constituting my present invention has been shown as a bipolar motor, and the primary and-seconds.

members have been shown provided wit Gramme ring windings. be understood that my invention is ap lice.- ble to a motor having any desired num er of poles and that any desired arrangement of windings may be used. In the actual construction of a motor the primar winding will preferably be a distribute winding It will, however,

wound in slots in the manner now commonly followed in winding the primary members of induction motors, and the secondary member will in general be similar in construction to the armature of a direct-current motor.

I, therefore, desire it to be understood that my invention is not limited to the particular constructions and arrangements shown in the drawings, and I aim to cover by the claims hereto appended all modifications which do not depart from the spirit and scope fof my.

invention. I

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an alternating --current motor, a primarymember provided with a windi distributed over a portion only of the said member, a secondary member provided with a winding connected to the segments of a commutator, short-circuiting brushes on'said commutator arranged to maintain in local closed cireuits those portions of the said secondary winding that are adjacent to. the primary field windin and means for producin an auxiliary field dis laced from the field no to the primary win ing.

2. In an alternatin current motor, a primary member provided witha windi distributed over a portion only of the-sa id member, a secondary member provided with .a winding connected to the segments of a commutator, short-circuiting brushes on said commutator arranged to maintain in local closed circuits those portions of the said secondary winding that are adjacent to the primary field winding, andmeans for produeing an auxiliary eld along *a line substantially atright angles to the line-of the primaryfi'eld. g I

3. In an alternatingcurrent motor, a .ririmary member provided with a windi-n (istributed over a portion only of the sai member, a secondary member provided with a winding connected to the segments of a commutator, short-circuiting brushes on said commutator arranged to maintain n local closed circuits those portions of the said sec'-. ondary winding that are a iM'bnt tothe main exciting windin and an auxiliary field winding included in t e local closed circuits. 4. In an alternatin current motor, a

primary member provided with 3 Wm istributed over a portion only of the'sai member, a secondary member provided With- .a winding connected to the segments ofa commutator, sln'irt-circuiting brushes on said conunutatorarranged to maintain in local closed circuits those portions of the said secondary winding that are adjacent to the main exciting winding, and an auxiliary lield. winding inchuled in said local closed circuits,

a magnetization along a line substantially at right angles to the line of magnetization of the primary winding.

5. In an altcrnating-current motor, a primary member provided with a winding distributed over a portion only of the said member, a secondary-member provided with a winding connected to the segments of a commutator, short-circuitirw brushes on said commutator, a choke coil to the windings of which the said brushes are connected, and an auxiliary field win ding connected to middle points in the choke coil winding.

6. In an alternating-current motor, a pri mary member provided with a main exciting winding distributed over a portion only of the said member, a secondary member provided with a winding connected to the segments of a commute tor, means for maintaining in local closed circuits those portions of the secondary winding adjacent to the main and means for producin an at an angle to the held 0 the main exciting winding and varying in strength field winding, (1

with the current induced inthe secondary winding.

7. In an alternating-current motor, a primar member provided with a main distribute winding, an auxiliary winding concenslots on said primary memtrated in large ary member provided with a her, a secon winding connected to the segments of a commutator, and short-circuiting brushes on said commutator.

8; In an alternating-current motor, a pr1 m'aiy member rovided with a main exciting winding distri uted over aportion onlyof said member, an auxiliary winding concentrated in large slots adjacent to the ends of the said main winding, a secondary member provided with a winding connected to the segments of a commutator, and short-circuiting brushesbearingonthe commutator segments connected to those portions of the secondary winding opposite the said slots.

said. member, an

,9. In an alternating-currentmotor, a primafiy member provided with a main distribute winding, an auxiliary winding concentrated in large slots adjacent to the ends of the saidflmain winding, a secondary member provided with a winding connected to the segments of a commutator, and shortcircuitin brushes bearing thereon included in circult with the said auxiliary field winding.

10. In an'alternatin -current'motor, a prima member rovide with a main exciting ingdistri uted over a portion only 0 auxiliary Winding co e n-.3

trated in large slots adjacent to the ends of the said main excitin winding, and a shortbetween said slots and circuited coil located so woundas to oppose magnetic leakage around the slots without interfering with the flux due to the main exciting winding, the said winding being arranged to produce 1 1. in an alternating-current motor, a pri mary member provided with a main excitin winding, an auxiliary winding concentratec in large slots, and a short-circuited coil located between said slots and so wound as to oppose magnetic leakage around the slots without interfering with the flux due to the main exciting Wimling.

12. As a means for preventing magnetic leakage through an unwound portion of a pri mary member between two win dings, a shortcircuitedcoil coinprising two halves wound in op ositc directions so as to op )ose mag-- netic eakage around the two win ings with out interfering with a'fiux normal to the unwoundportion of the said member.

13. In an alternating-current motor, a p'ri.-. mary member provided with a main inducing winding distributed over a portion only 0 said member, an auxiliary exciting winding concentrated inlarge slots-on the portion of the-primary member not occu )ied by the main winding, a secondary mem er provided with a winding connected to the segments of a commutator, and brushes and connections arranged to include the secondary winding in a local closed circuit.

14. In an alternatin gscurrent motor, a primary member rovided with a main inducing winding distributed over a portion only of said member, an auxiliary exciting winding concentrated in large-slots on the portion of the primary member not occupied by the main winding, a secondary member provided with a winding connected to the segments of a commutator, and brushes and connections arranged to include thesecondary winding in a local closed circuit withsaid auxiliary exciting winding.

. l5 In -an alternating-current motor, a pri 1iiary member rovided with a main inducingwinding distri uted over a portion only of said member, an auxiliary exciting winding occupying occupied by the main inducing said member, an au'xiliar exciting winding occupying the portion '0 said member not the portion of said member not wmdm asecondary member provided with a wm mg occupied by the main inducing windin a secondary member provided with a win ing connected to the segments of a commutator, and brushes and connections arranged to'include the secondary winding in a local closed circuit, the circuits of the secondary winding being arranged to produce a magneto-motive force distribution similar to that of the inducing winding.

17. In an alternatin -current motor, a primary member )rovidc with a main inducing winding distri uted over a portion only of said member, an auxiliary exciting winding occupying the portion of said member not occupied by the main inducing winding, a

secondary member provided with a winding connected to the segments of a commutator, and brushes and connections arranged to include the secondary winding in a local closed circuit, the circuits of the secondary winding 20 being arranged to render effective only those portions of the-secondary winding adjacent to the main inducing winding of the primary member.

In'witnes's whereof, I' have hereunto set 25 

